| One of the main goals of tissue engineering is to create new functional scaffolds with desired chemical and physical features mimicking the native micro-environment and modulating cell functions or behaviors. As collagen is abundant in the extracellular matrix (ECM) of native tissues, it is widely used to generate artificial scaffolds in in vitro. In this thesis research, aligned collagen and collagen-composite fibirls (COL-CNT and COLI-COLIII) were achieved via epitaxial growth of collagen on muscovite mica surface. It was found that hdpPSCs interacted with collagen fibrils by deforming the cell shape, harvesting the nearby collagen fibrils, and reorganizing the fibrils around the cell body to transform a 2D matrix to a localized 3D matrix. Such a unique 3D matrix prompted high expression of beta-1 integrin around the cell body that mediates and facilitates the stem cell differentiation toward neural cells. By compositing collagen with carbon nanotube (CNT), aligned COL-CNT fibril was obtained with 3 times stiffer than pure collagen fibril and a 2 nm D-period increase. The anisotropic morphology and high stiffness of COL-CNT fibrils greatly facilitated the elongation of SKOV3 cells by regulating the cell-matrix adhesion, cytoskeleton arrangement and cell migration rate, finally promoted the epithelial-mesenchymal transition (EMT) of the SKOV3 cells. Aligned COLI-COLIII hybrid collagen fibrils exhibit higher stiffness than pure COLIII and stronger binding affinity than pure COLI. It is found that with the combined advantages of stiffness and binding affinity, aligned COLI-COLIII fibrils lead to fibroblast cytoskeleton elongation and enhanced cellular elasticity with stronger traction strain sulfured, which improves collagen synthesis ability of fibroblast with a higher collagen I percentage. |
